A weather system is expected to slowly and erratically edge from the south during Thursday and bring the risk of widespread and disruptive snow across many parts of Wales. There are still some uncertainties regarding the finer detail but there is now increasing likelihood of significant disruption.

Outbreaks of light snow are expected in southern parts of Wales from early morning onwards and will gradually extend northwards through the day to affect many parts of Wales. Heavier snow is then expected to develop at times from late afternoon onwards with the snow continuing in many places through the evening and overnight. With time there is scope for a build up of significant amounts of snow, particularly across parts of the South Wales and Gwent LRF areas along with Powys. Here, up to 10 cm is possible quite widely by Friday morning with 20cm or more on the hills and notable drifting is also to be expected in the strong easterly winds. Elsewhere lesser amounts of snow are to be expected with 2 to 5 cm more likely but perhaps up to 10cm in places. There is also a risk of the snow turning to freezing rain at times during Thursday night and giving very icy conditions.

An Amber warning has been issued for the southern half of Wales indicating a medium likelihood of HIGH impacts and is valid from 1200on Thursday until 0800 on Friday although please note my comments that the risk of disruption in westernparts of Wales is lesser but will be kept under review. A yellow warning is also in place for the remainder of Wales indicating a low likelihood of Medium impacts.

Further light snow is expected on Friday. It will then become less cold over the weekend with a messy mix of rain, sleet, and snow at times and also an increased risk of icy roads.